This invention relates to apparatus for leveling ladders disposed on inclined or irregular surfaces and more particularly to a ladder leveling apparatus readily attachable to ladders having side rails of various configurations without requiring modification to the ladder.
Although it is desirable when erecting a ladder to rest the bottom of the side rails on a substantially flat horizontal surface, it is not uncommon for ladders to be used at locations that do not provide a level surface. Obviously the use of a ladder at such a location can be quite dangerous. Various expedients have been used such as placing blocks or shims under the feet of the side rail to level the ladder, but such temporary devices are quite unsafe.
Ladder levelers attachable to the side rails of ladders have been proposed in the prior art. Such levelers include an extendible leg moveable relative to the rail of the ladder to which it is attached. Examples of such levelers are disclosed in U.S. Pat. Nos. 2,849; 3,484,814; 3,861,500; 3,948,352; 3,998,293; and 4,209,078.
The ladder levelers of the known prior art have been deficient in the manner of attachment thereof to the side rail of a ladder. In certain of the prior art, such as in U.S. Pat. Nos. 3,484,814 and 4,209,078, the leveler can only be clamped to a rectangular leg of a wooden ladder. Modern ladders, however, are usually formed from extruded aluminum having rails of various shaped channel configurations. In certain of the other prior art such as in U.S. Pat. Nos. 2,936,8487; 3,861,500 and 3,948,352, holes must be bored into the ladder rails for bolting or otherwise attaching tubular or channel mounting members to the rail, the mounting members carrying the adjustable leveling leg. Such holes and other modifications required to the rails weaken the ladder and reduce its structural integrity.